[PATCH] D40857: [AArch64][Darwin] Add new ARM64 stack probing function for Darwin

[Amara Emerson via Phabricator via llvm-commits]

aemerson created this revision.
Herald added subscribers: Sanitizers, kristof.beyls, javed.absar, mgorny, rengolin.

[AArch64][Darwin] Add new ARM64 stack probing function for Darwin.

This is the ARM64 equivalent of the Darwin x86 stack probing function and likewise it doesn't modify the stack pointer. However it does have a custom calling convention (uses registers X9-X11).

rdar://25859140


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D40857

Files:
  lib/builtins/CMakeLists.txt
  lib/builtins/aarch64/chkstk_darwin.S
  lib/builtins/assembly.h


Index: lib/builtins/assembly.h
===================================================================
--- lib/builtins/assembly.h
+++ lib/builtins/assembly.h
@@ -18,6 +18,8 @@
 
 #if defined(__POWERPC__) || defined(__powerpc__) || defined(__ppc__)
 #define SEPARATOR @
+#elif defined(__aarch64__)
+#define SEPARATOR %%
 #else
 #define SEPARATOR ;
 #endif
Index: lib/builtins/aarch64/chkstk_darwin.S
===================================================================
--- /dev/null
+++ lib/builtins/aarch64/chkstk_darwin.S
@@ -0,0 +1,33 @@
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+
+#include "../assembly.h"
+
+#ifdef __aarch64__
+
+#define PAGE_SZ 4096
+
+// ___chkstk_darwin - a generic stack probing function.
+// The number of bytes to probe is passed in w9.
+// This clobbers registers x9, x10 and x11.
+// Does not modify any memory or the stack pointer
+
+.balign 4
+DEFINE_COMPILERRT_FUNCTION(___chkstk_darwin)
+.weak_definition ___chkstk_darwin
+        cmp     w9, #PAGE_SZ
+        mov     x10, sp
+        b.lo    Lend
+Lloop:
+        sub     x10, x10, #PAGE_SZ
+        ldr     x11, [x10]
+        sub     w9, w9, #PAGE_SZ
+        cmp     w9, #PAGE_SZ
+        b.hi    Lloop
+Lend:
+        sub     x10, x10, x9
+        ldr     x11, [x10]
+        ret
+END_COMPILERRT_FUNCTION(___chkstk_darwin)
+
+#endif // __aarch64__
Index: lib/builtins/CMakeLists.txt
===================================================================
--- lib/builtins/CMakeLists.txt
+++ lib/builtins/CMakeLists.txt
@@ -444,6 +444,7 @@
 endif()
 
 set(aarch64_SOURCES
+  aarch64/chkstk_darwin.S
   ${GENERIC_TF_SOURCES}
   ${GENERIC_SOURCES})
 


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